linux-wandboard

driver core: delete virtual directory on class_unregister()

Class virtual directory is created as the need arises.
But it is not deleted when the class is unregistered.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>